Na(+)/urea-polyamine cotransporter DUR3, and related proteins; solute-binding domain
Dur3 is the yeast plasma membrane urea transporter. Saccharomyces cerevisiae DUR3 also transports polyamine. The polyamine uptake of S. cerevisiae DUR3 is activated upon its phosphorylation by polyamine transport protein kinase 2 (PTK2). S. cerevisiae DUR3 also appears to play a role in regulating the cellular boron concentration. This subfamily belongs to the solute carrier 5 (SLC5) transporter family.
Comment:based on the structures of Vibrio parahaemolyticus vSGLT (SLC5), Aquifex aeolicus LeuT (SLC6), and the NCS1, Microbacterium liquefaciens Mhp1, bound with Na+, functional studies of Escherichia coli PutP (SLC5) and mammalian NIS (SLC5), and mutational analysis of vSGLT
Comment:one of two Na+ binding sites in Aquifex aeolicus LeuT, where it is referred to as the Na binding site 2